<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
		<!--<script src="a.js" defer="defer"></script> 延迟加载这个js，在onload之前加载
		<script src="b.js"></script>
		<script src="c.js"></script>-->
		<script>
			window.onload = function(){
				var box = document.getElementById("box");
				//alert(box.dataset.che);
				alert(box.dataset.cheShuang);
			};
			/*defer:延迟加载,会按顺序执行,在onload执行前被触发
			async:异步加载,加载完就触发,有顺序问题*/
		</script>
	</head>
	<body>
		<div id="box" data-che = "车" data-che-shuang = "车爽"></div>
	</body>
</html>
